February 27, 2012
A few centuries ago, water use was not a problem because it was seen as a renewable resource that can never be overexploited. However, as population growth increases exponentially, water use likewise increases, depleting water resources at an unsustainable rate. As we use groundwater and surface water at a rate faster than their replenishment rate, we must look towards other sources to obtain water. One proposed solution is desalination, a process that removes salt from saline water. There are three techniques associated with desalination: electrodialysis, freezing, and reverse osmosis. Electrodialysis uses porous members to remove positively and negatively charged salt ions; freezing, by default, removes salt from ice; and reverse osmosis is a process that pressurizes salt water so that water flows through a membrane while the remaining salt are retained (Desalination Process).
Desalinization, while is considered an alternative water supply, has its fair share of negative environmental impacts that could potentially harm large communities of marine organisms. First, the discharge from the desalination facilities carries saline water back into the ocean, which affects benthic organisms that are not accustomed to water with such high salinity. Similarly, discharged water can contain chloride, heavy metals, and cleaning chemicals that would foul ocean water and poison marine animals.
Furthermore, the power consumption required for the process of desalination consumes fossil fuels, which leads to carbon dioxide emissions. As known, carbon dioxide has detrimental effects on the environment, including warming of the earth and human health risks.
Desalination also requires an extensive amount of energy to work. If desalination were to produce half of America’s water, the United States would need to construct 100 more electric power plants (Why Desalination Doesn’t Work). And the energy cost of consuming the necessary amount of energy to produce usable water would exceed the cost to pump water from aquifers or to import the water. Therefore, desalination is not a very cost-effective method and should be used with caution.
In one example, Huntington Beach has proposed desalination in order to provide water to their community. This desalination facility, if successful, would provide 50 million gallons of drinking water per day (Proposed Desalination Plant Wins Permit). However, opponents criticize desalination as energy-intensive and expensive. Furthermore, the construction of the facility near a popular beach would inevitably harm aquatic organisms, which could reduce tourism and recreation.
While it’s necessary to address the current water crisis and some may claim that the damage to marine organisms is insignificant in comparison to the benefits to society, desalination conflicts with the energy-crisis, which would mean that through desalination, we are essentially trading one problem in for another. Especially since most desalination plants require the use of fossil fuels, desalination would exacerbate the energy-crisis, depleting energy resources from other uses.
Despite their criticism, opponents do acknowledge the current water problem, so they propose alternative solutions, including improving irrigation systems and requiring new homes to be water-efficient. These solutions are more focused on conservation of water, which can help communities be more conscientious of their water usage and supply more water to each individual.
Kaylee Yang and Marc Chua are undergraduates in the USC Dornsife College of Letters, Arts and Sciences.